bootstrap modal and mmenu menu clashing

I'm designing a site using bootstrap and mmenu libraries. I'm trying to add a bootstrap modal that opens when clicking a button in mmenu.

The modal doesn't close when clicking close, pressing ESC and clicking outside the modal.

I tried writing a page with the same modal and mmenu, where the modal opens by clicking a button on the page, not in the mmenu, and both worked fine.

I tried a mmenu popup that appears when the button inside the mmenu is clicked, but had the same problem.

I'd be happy with a generic answer as well;
Where problems with these two libraries can arise, and how to get around them. Or how to debug the code so that I can figure out the solution myself. I tried checking the Console in Chrome but there were no errors there. I don't know how to check any further.

I added my code just in case someone who is familiar with the mmenu and bootstrap libraries has a specific answer. Thank you all for your effort.